> How much has human activity raised global temperatures?

How much has human activity raised global temperatures?

Posted at: 2015-03-12 
This is a very simple question

Answers in Celsius or Fahrenheit if you wish

0.00000000000001 degree C.

It's almost April....they are predicting more snow here in Michigan next week.....is there any way us humans can speed up the global warming thingy?

Oh, did some web surfing to day. The wizards at the weather bureau made a long range prediction last year that we would have average temperatures and slightly below precipitation. Totally wrong on both counts.

Look at the Old Farmers Almanac and they predicted it perfectly...just like in the past several years.

What does the Old Farmers Almanac think of global warming? Nonsense.

So who do we believe? Wizards that can barely predict the weather for next week, or a group of people who have been predicting weather correctly for decades.

Bet you won't see any of this on the mainstream media.

The annual temperature of the world and the United States is now 1.0 F hotter compared to the temperature a century back.

The average temperature in three large countries has increased at two times the global average.

The temperature of the earth will soon become 5.8 degrees higher.

Each year of the 21st century is among the hottest in history.

Two of the world’s hottest temperatures were recorded in the last ten years.

The past nine years have all been among the 25 hottest temperatures in history.

We can figure out by taking the Sun out of the equation and figure out how much warming has occurred since the Sun was at the same level as it is now, which was about 1923.

http://www.woodfortrees.org/plot/sidc-ss...

The temperature anomaly in 1923, on the trendline, was -0.3C and is now +0.5C, on the trendline. The difference is 0.8C.

< Trevor's answer is clearly contradictory and speculative.>

And any answer from a skeptical source, isn't.

Trevor



I would be very careful about putting any certainty of how much natural warming over what time period led the the Medieval Warm Period. Different reconstructions show different peaks and valleys in the past. But what is striking about current warming isn't the speed, but the duration of the warming. Rather than 50 year cycles, we have seen over a century of persistent warming.

Madd Maxx



The question is about global warming, not about new energy sources. But since we are here;

Given that in a single day, the Sun sends enough energy to Earth to supply our energy needs for 200 years, why are you so afraid to switch to solar power.

I don't really see what the issue is here, particularly with Trevor's answer. His analysis doesn't sound at all unsure, confused or contradictory to me and anticipates variables that have been known for quite some time. It sounds to me as if you are deliberately trying to mischaracterize a good response by trying to undermine Trevor because the answer can't be made as simple as you want it to be...and I would guess that quite a lot of people would agree with that conclusion. Sorry.

Interestingly enough, I was just about to suggest that you re-read Trevor's remarks and point out the contradictions for those of us who do not see them.

Science can't tell you what the average temperature is or what it should be. It's something they can't measure accurately. Warm and cold air moves around the planet so fast, that they can't catch up to it and accurately measure it. That's why they use anomalies.

Science teaches about human evolution and the same science defies that logic by stating that humans are causing the planet harm and to warm with our activity. Duh!!! Here's the good news: A warmer planet means increased plant and animal activity. Do we trust science when they say that 250 million years ago there was much more life in a warmer environment?

I dont know and I am sure scientists dont know either, until we have a means of separating natural and man-made warming we can only guestimate.

What I do know is that has be pretty small somewhere between 0.2C and 0.6C would be my guess

>> Trevor . Yes it is simple, if it's an undeniable reality, then quantifying the amount should have been among the first proofs.<<

There are no “proofs” in science – of anything. There is no scientific proof that the planets move around the sun (Copernican theory) or that germs cause disease.

Why do you stupid knuckleheads think that you know anything about climate science when you do not even know what science is?

The temperature has increased 0.8C not 1.8C in the last 100 years.

http://data.giss.nasa.gov/gistemp/graphs...

Edit: Yeah, I made that up. Notice I didn't include the word 'humans'?

I find it hard to believe that scientists could separate anthropogenic warming from natural warming. We are dealing with hundreths of a degree. Proxies can't be that accurate.

http://en.wikipedia.org/wiki/File:Holoce...

Zero.

It takes mankind over 200 years of electricity production WORLDWIDE to match the amount of energy the Sun sends us in a SINGLE DAY !!

That's how irrelevant the heat produced by humans is.

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This is a very simple question

Answers in Celsius or Fahrenheit if you wish

The natural temperature increase over the last 200 years has been maybe .5C/ century. So I'll go with .3C.

Pindar,

The question isn’t quite as simple as it sounds, this is because there are a great many factors involved in climate change, some of which we don’t understand or can’t quantify all that well.

There are numerous ways to calculate how much warming human activities have caused. This question can be approached from different angles but all come back with answers of about 1.05°C. It’s important to note that this isn’t the same as the amount of warming that has been observed.

Taking the long-term global mean temperature: by the end of 2013 the Earth was 14.545°C whereas 100 years ago it was 13.677°C, this represents a warming of 0.868°C. But this figure incorporates both the warming and cooling signals and both the natural and manmade influences.

If we focus only on the natural variations we find that over the long-term there should have been little variation in temperatures. For millennia the natural variation was no more than about 0.1°C per century and nothing has changed in the 20th or 21st centuries that could affect this.

In the shorter-term, say the last 10 to 20 years, natural factors should have caused quite a significant cooling but this hasn’t occurred. Instead, the cooling has been countered by the manmade warming such that temperatures have temporarily stabilised. If it wasn’t for the natural cooling then we would have seen further increases in the global temperature of about 0.2°C; add this to the 0.868°C that has been observed and you get a figure of just over 1°C.

The same thing happened about 50 years ago when natural variations were also in a strong cooling phase. There should have been cooling but there wasn’t, the underlying manmade warming trend prevented this; just as it’s doing now. Instead of natural ups and downs in the temperature we’re seeing them rise in a series of steps.

Over periods of several decades we should observe natural warming and cooling cycles of approx 0.1°C per decade with an overall change of no more than 0.1°C per 100 years. What we’re actually observing are static temps during natural cooling phases and rises of about 0.2°C during the warming ones. The underlying manmade warming signal therefore having averaged some 0.1°C per decade.

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RE: YOUR ADDED DETAILS

It’s not necessary, or possible for that matter, to quantify precisely how much warming is attributable to mankind. That doesn’t mean, as you seem to be implying, that global warming therefore can’t exist.

I assume you agree that people are living longer than they did 100 years ago, but what is the precise figure for current global longevity? Nobody knows because there are many places that don’t keep accurate birth and death records. Similarly, what was the average age 100 years ago, we can pinpoint this with even less precision. Because we don’t have precise values doesn’t invalidate the fact that people, on average, are living longer.

Sorry of my figures confused you. I’ll explain them again. In the last 100 years manmade global warming has caused about a temperature increase of about 1.05°C but in recent years there has been a very strong natural cooling influence that counters about 0.2°C of this, therefore the observed rise in temps is approx 0.85°C.

On a decadal scale there are natural variations that cause a temperature swing of about 0.1°C, these variations have both positive and negative phases that over a full cycle cancel each other out. Over a longer period of time, such as a century, then the small differences between positive and negative phases can add up to a relatively significant amount of warming or cooling – as much as 0.1°C.

People talk about recovering from the Little Ice Age or the Medieval Warm Period and they do so often in the context of identifying historical climate variations and using them as an excuse to dismiss the recent variations as also being natural. But when have you seen anyone who references the LIA or the MWP actually put the magnitude of change into context – they don’t.

The MWP was the culmination of 1,000 years of natural warming which saw the average global temperature increase by 0.4°C. In the last 100 years the rate of warming has been 21 times as fast. Similarly, by 1900 we had more or less recovered from the LIA and temperatures were back to where they had been for the preceding 2,000 years. The warming of late has been 10 times as great as the warming that ended the LIA.

Up to about 1850 we saw temperatures rise and fall in line with natural oscillations, superimposed on this were the long term warming, then cooling, then warming trends that caused change of about 0.1°C per century.

Since approx 1850 we haven’t seen the up and down cycle as the cooling phases have been cancelled out by manmade warming, instead we’ve had a succession of upward steps – no cooling. This is something that can’t be explained by natural variation, no matter how much the sceptics wish it could.

no proof of any amount. earth is still recovering from the little ice age and hasn't even warmed up to what it was during the medieval warm period yet. We should be worried that the warming stopped 17 years ago.

human activities have affected so much like deforestation,glaciers melting and forest fires.

we should save our environment by not using chloro fluoro carbon and some green house gases like nitrous oxide,carbon dioxide etc..

Unknown. There is only conjecture based on manipulated/doctored 'data'.

@ 1.8 C in last 100 years